Background This descriptive cross-sectional study aimed to assess the exposure to formaldehyde associated with the tasks in a pathology laboratory unit. The study objectives were to describe the tasks involving the use of formaldehyde in the unit and assess exposure to formaldehyde as well as assess the effectiveness of existing engineering/ventilation system control methods. Methods The study involved observation and description of all tasks carried out in the laboratory, assessing exposure to formaldehyde and physical measurements of laboratory parameters such as area and volume. Exposure assessment involved three levels: task-based exposure assessment; personal exposure assessment and area exposure assessment. Formaldehyde measurements, by means of shadow sampling (personal breathing zone sampling by another person shadowing person being sampled) were taken using the formaldehyde meter. Data were summarised using means, medians and proportions and results were presented in figures and tables. For significance testing, an analysis of variance was carried out on the log-transformed data and p-value less than 0.05 were interpreted as statistically significant. Results Not all tasks in the laboratory were done according to the standard operating procedures. In general, exposure to formaldehyde was highest among the assistants group who were mostly responsible for high-exposure tasks. Mean STEL values for assistants, technologists and pathologist were 2.37ppm, 1.21ppm and 1.59ppm respectively, while for TWA, the figures were 0.60ppm, 0.36ppm and 0.21ppm. For short term exposures (STEL and peak values) pathologist exposure levels were higher than those of technologists while technologists were higher for long term exposures (daily exposure and 8-hour TWA). Daily exposure varied significantly for assistants and technologists but not for pathologist. Despite the use of engineering exposure controls for formaldehyde, 27/28 of all tasks were higher than the ACGIH threshold ceiling limit of 0.3ppm, 0.008ppm MRL value and 0.002ppm RELTWAConclusion The results have shown exposures among the employees of all job categories in this study, with laboratory assistants being the most exposed. Currently installed local ventilation system requires to be upgraded in accordance with best practices of 3.5m/s for air speed. Training, on PPE usage together with the medical surveillance should also be implemented. value.

Surface ozone (O3) is one of the most toxic and abundant air pollutants. It has deleterious effects on human and animal respiration processes, and adversely affects plants. Four sites were selected for monitoring ambient O3 in the Durban metropolitan area: Botanic Gardens, University of Natal (UND), top of Kloof Gorge, and Mooi River. At each site tobacco Bel-W3 bioindicators, and NO2 and O3 passive diffusion tubes were placed. An O3 analyser (Dasibi 1108) was situated at the UND site. Monitoring was carried out for four weeks during summer, autumn and winter at each site, and during spring at the UND site. Two weeks of data from the diffusion tubes were collected during spring, from the Nelspruit area, Mpumalanga. Ozone concentrations measured with the Dasibi at the UND site were low in comparison to other urban-industrial areas in the world, with hourly values falling between 5ppb and 10 ppb. The highest hourly mean maximum recorded was 40ppb. A general spring/winter maximum and summer minimum was observed. This is typical of subtropical locations, where subsidence in prevailing anticyclonic circulation occurs. Diurnal characteristics included early morning minima and maxima at 12h00 in spring and summer, and maxima approximately two hours later in autumn and winter. This pattern was typical of that found in polluted environments, the magnitude, however, being lower. An unusual secondary nocturnal peak occurred during autumn, winter and spring. This could have been due to the long-range transport of relatively O3-rich air from a non-urban, high altitude inland area. Ozone concentrations were not strongly influenced by meteorological variables. Diffusion tube data indicated low O3, however, the coefficients of variation were high, implying a lack of precision in this technique. This technique would have to be improved before data obtained could be regarded as valid. Nitrogen dioxide, NO2, one of the precursors to O3, was monitored using diffusion tubes at the same sites. Concentrations were highest closer to the city centre, the highest concentration being 31ppb in autumn. In the Mpumalanga study, NO2 concentrations were higher in the city of Nelspruit than the surrounding areas. No significant differences were found in the O3 concentrations between the Mpumalanga sites. The tobacco plants showed the highest visible leaf injury in winter, corresponding with the higher Dasibi values, but there were no significant differences between the sites, and no significant differences in chlorophyll contents between the sites. In this study, O3-induced injury occurred below the previously established threshold of 40ppb. / Thesis (M.Sc.)-University of Natal, Durban, 1998.

Este estudo avalia os efeitos adversos na saúde causados pelas variações na composição do material particulado em curtos períodos de tempo. Para tanto, foram determinados Black Carbon (BC), massa e composição elementar do PM2.5 coletado em dois diferentes períodos, Dia e Noite, na cidade de São Paulo. Além das análises químicas, gravimetria, análise de reflectância e espectrometria por fluorescência de Raios-X, foram realizados testes toxicológicos de contagem de micronúcleos utilizando ressuspensão do PM2,5 em raízes de Allium cepa (cebola). O PM2.5 foi amostrado na saída do Concentrador de Partículas Finas Ambientais de Harvard (CPFAH) e as amostras foram coletadas diariamente por quinze dias, entre Maio e Junho (Experimento 1) e entre Outubro e Novembro (Experimento 2) de 2009, durante o Dia (8:00h - 11:00h e 14:00h - 17:00h) e a Noite (20:00h - 23:00h). A variabilidade na composição do PM2.5 foi analizada utilizando o método de componentes principais, por meio da qual foram identificados três fatores significantes: Fator 1, onde encontramos BC e os elementos Ca, Fe, K, Si, Zn e Ti que podem ser característicos da emissão do tráfego veicular em geral; Fator 2 onde encontramos Ni e Cr que podem ser interpretados como resultado das emissões industriais; e o Fator 3 é formado pelos elementos V e S que podem ser característicos das emissões das queimas de diesel e óleo combustível. A análise univariada da contagem dos três fatores mostrou uma diferença significativa somente para o Fator 3 (p=0,022) entre os dois períodos, fazendo-se mais presente no período noturno. A frequência do número de micronúcleos das células de raízes de cebola foi maior para período noturno. Os resultados indicam que existem diferenças na composição e toxicidade do PM2,5 coletado em diferentes períodos na cidade de São Paulo. Os dados sugerem que a toxicidade do PM2,5 pode ser influenciada pelas mudanças nos padrões de tráfego e processos fotoquímicos da atmosfera. / The objective of this study was to evaluate the adverse health effects of shortterm variations in particle composition. For this purpose, black carbon, particle mass and elemental composition of PM2.5 collected along the two different periods in São Paulo city were determined. In addition to the chemical measurements, toxicological evaluation was performed using the Allium cepa micronuclei assay test and particle suspensions of PM2.5 as test substrate. PM2.5 was sampled at the output of the Harvard Ambient Fine Particle Concentrator (HAFPC). The samples were collected daily from May 19th to June 4th (period 1) of 2009, during the morning (from 8 AM to 11 AM), afternoon (from 2 PM to 5 PM), and evening (from 8 PM to 11 PM), and from November 11th (period 2) of 2009, during the morning (from 8 AM to 11 AM), and evening (from 8 PM to 11 PM). Samples collected during the morning and afternoon were called Day and those collected during the evening, EVENING. Concentrations of PM2.5 mass (gravimetric method), black carbon (reflectance analysis) and trace elementals (X-ray fluorescence spectrometry) were determined. Variability in PM2.5 composition measured was analyzed using Principal Components Analysis in which 3 significant factors were identified. Results of black carbon (BC) and of elements Ca, Fe, K, Si, Zn and Ti were grouped in Factor 1, that can be characteristic of general traffic emission; In Factor 2, Ni and Cr were included and it can be interpreted as a result of industry emissions; and Factor 3 is formed by V and S what characterizes diesel/oil combustion emissions. Univariate Analysis of factor scores indicated a significant difference between the periods scores of factor 3 (p=0.022). The frequency of number of micronuclei obtained was also higher in samples collected at the EVENING than those of DAY. In conclusion, our results indicate that there are differences in the composition and toxicity of PM2.5 collected in different periods of the day. These findings suggest that particle toxicity may be influenced by changes in traffic patterns and photochemical processes.

Este estudo avalia os efeitos adversos na saúde causados pelas variações na composição do material particulado em curtos períodos de tempo. Para tanto, foram determinados Black Carbon (BC), massa e composição elementar do PM2.5 coletado em dois diferentes períodos, Dia e Noite, na cidade de São Paulo. Além das análises químicas, gravimetria, análise de reflectância e espectrometria por fluorescência de Raios-X, foram realizados testes toxicológicos de contagem de micronúcleos utilizando ressuspensão do PM2,5 em raízes de Allium cepa (cebola). O PM2.5 foi amostrado na saída do Concentrador de Partículas Finas Ambientais de Harvard (CPFAH) e as amostras foram coletadas diariamente por quinze dias, entre Maio e Junho (Experimento 1) e entre Outubro e Novembro (Experimento 2) de 2009, durante o Dia (8:00h - 11:00h e 14:00h - 17:00h) e a Noite (20:00h - 23:00h). A variabilidade na composição do PM2.5 foi analizada utilizando o método de componentes principais, por meio da qual foram identificados três fatores significantes: Fator 1, onde encontramos BC e os elementos Ca, Fe, K, Si, Zn e Ti que podem ser característicos da emissão do tráfego veicular em geral; Fator 2 onde encontramos Ni e Cr que podem ser interpretados como resultado das emissões industriais; e o Fator 3 é formado pelos elementos V e S que podem ser característicos das emissões das queimas de diesel e óleo combustível. A análise univariada da contagem dos três fatores mostrou uma diferença significativa somente para o Fator 3 (p=0,022) entre os dois períodos, fazendo-se mais presente no período noturno. A frequência do número de micronúcleos das células de raízes de cebola foi maior para período noturno. Os resultados indicam que existem diferenças na composição e toxicidade do PM2,5 coletado em diferentes períodos na cidade de São Paulo. Os dados sugerem que a toxicidade do PM2,5 pode ser influenciada pelas mudanças nos padrões de tráfego e processos fotoquímicos da atmosfera. / The objective of this study was to evaluate the adverse health effects of shortterm variations in particle composition. For this purpose, black carbon, particle mass and elemental composition of PM2.5 collected along the two different periods in São Paulo city were determined. In addition to the chemical measurements, toxicological evaluation was performed using the Allium cepa micronuclei assay test and particle suspensions of PM2.5 as test substrate. PM2.5 was sampled at the output of the Harvard Ambient Fine Particle Concentrator (HAFPC). The samples were collected daily from May 19th to June 4th (period 1) of 2009, during the morning (from 8 AM to 11 AM), afternoon (from 2 PM to 5 PM), and evening (from 8 PM to 11 PM), and from November 11th (period 2) of 2009, during the morning (from 8 AM to 11 AM), and evening (from 8 PM to 11 PM). Samples collected during the morning and afternoon were called Day and those collected during the evening, EVENING. Concentrations of PM2.5 mass (gravimetric method), black carbon (reflectance analysis) and trace elementals (X-ray fluorescence spectrometry) were determined. Variability in PM2.5 composition measured was analyzed using Principal Components Analysis in which 3 significant factors were identified. Results of black carbon (BC) and of elements Ca, Fe, K, Si, Zn and Ti were grouped in Factor 1, that can be characteristic of general traffic emission; In Factor 2, Ni and Cr were included and it can be interpreted as a result of industry emissions; and Factor 3 is formed by V and S what characterizes diesel/oil combustion emissions. Univariate Analysis of factor scores indicated a significant difference between the periods scores of factor 3 (p=0.022). The frequency of number of micronuclei obtained was also higher in samples collected at the EVENING than those of DAY. In conclusion, our results indicate that there are differences in the composition and toxicity of PM2.5 collected in different periods of the day. These findings suggest that particle toxicity may be influenced by changes in traffic patterns and photochemical processes.